Scrap sampling method



March 12, 1968 E. E. BROWN 3,372,993

SCRAP SAMPLING METHOD Filed Sept. 11, 1963 CRUSHING ANALYZING FIG.3

COOLING CONVERTING SAMPLE OXIDES FIG. I

TEST

SAMPLE SHREDDING I NVEN TOR.

EDWARD E. BROWN BY ATTORNEYS SAMPLING FROM CAR

United States Patent *Ofiice 3,3 72,993 Patented Mar. 12, 1968 3,372,993 SCRAP SAMPLING METHOD Edward E. Brown, Marietta, Ohio, assignor to Interlake Steel Corporation, a corporation of New York Filed Sept. 11, 1963, Ser. No. 308,161 16 Claims. (Cl. 23-230) This invention relates in general to a method of sam pling scrap, and more especially to a method of sampling and analyzing for tramp elements conventionally found in a quantity of ferrous scrap, to give a representative figure of such tramp elements.

In the production of various alloys, scrap metal is often utilized as a part of the materials used in producing such alloys. For example, in the production of high purity silvery iron or ferro silicon, steel scrap is conventionally utilized. The greatest source of contamination by unwanted tramp elements in such alloy production is generally the existence of such tramp elements in the Scrap. Accordingly, it is conventionally necessary to analyze samples of the scrap used, in an attempt to estimate the amounts of such tramp elements in the scrap prior to its use.

Past practice for such inspection procedure has included taking samples from various positions in a railroad car full of scrap metal and in which it was hoped that the scrap articles were of generally uniform type, such as for instance turnings or borings. If any odd size pieces of scrap were noted in the car, such scrap would be turned over with a clam bucket and the odd size pieces picked out and tested separately. Thus, the number of tests was generally dictated by the number of different sizes and shapes of these odd pieces, and because of the time and effort involved, this procedure was completely unsatisfactory, and even so, the cars were generally not properly classified as to the type of elements in the scrap.

After taking a representative sample of such scrap material from a car, the next step usually involved the removal of the grease or oil, if any, from the scrap metal, such as for instance by washing it in solvent, and then drying the metal to remove the solvent. The next problem in such prior art procedure was then getting the sample taken, into a suitable physical form for conventional chemical or instrumentated analysis of the sample, and this generally involved snipping off small pieces from various pieces of the sample taken, until the desired sample weight was obtained. The amount of sample weight desired for the aforementioned chemical or instrumentated analysis generally was kept to about 5 grams.

Another known prior art procedure includes the taking of a representative sample of between 50 to 100 pounds from acar of scrap, and then melting such sample in an induction furnace, after which specimens are poured from such melt for use in spectrographic analysis, or for drilling for chemical analysis. This type of procedure requires considerably expensive equipment, and in addition the samples which are usually exposedto outdoor weather conditions are generally coated with rust, and when melted in the furnace, some of the tramp elements in the melt, such as for instance chromium, titanium, aluminum, etc. combine with the oxygen and are slagged off, thereby not giving the true value for the tramp elements in the melt.

The present invention provides a novel method wherein the sample of scrap which is taken, is burned in an at- Another object of the invention is to provide a novel method of sampling metallurgical scrap which includes burning of a scrap sample in an atmosphere of oxygen to convert the important elements of the scrap entirely into their oxides and thereafter analyzing oxides.

Another object of the invention is to provide a novel method of analyzing metallurical scrap, and in a manner to insure against any significant loss of tramp elements from the sample of scrap metal.

A still further object of the invention is to provide a novel method of analyzing metallurgical scrap for use in the production of various ferrous ailoys, which includes the steps of taking a predetermined scrap sample from a given quantity of scrap that is to be utilized, shredding the scrap metal to obtain a readily handled specimen, taking a predetermined weight of the shredded scrap sample so obtained and burning it in the presence of oxygen so as to convert the elements of the metal sample entirely into their oxides, allowing the oxides to cool, crushing the resultant oxide sample into a predetermined size of particles, and then analyzing such crushed sample specimen to obtain an accurate reading of the percentages of tramp elements in such given quantity of scrap.

Other objects and advantages of the invention will be apparent from the following description taken in conjunction with the accompanying drawing wherein:

FIG. 1 is a block diagram illustration of a method involving the instant invention;

FIG. 2 is a side elevati-onal view of a crucible which may be utilized in converting the test sample to its oxides; FIG. 3 is a top plan view of the crucible of FIG. 2.

In practicing the instant invention, a railroad car of scrap metal or other predetermined quantity of scrap metal, that is to be analyzed may be taken, and three holes may be produced in the scrap of the car, with such three holes being preferably equally spaced from one another, and using, for instance, a clam bucket. The individual or workman taking the sample may then take a sample of the scrap from both the top and bottom of each hole; thus in the aforediscussed embodiment, six samples are taken from the car. The total weight of the sample taken is dictated by the size of the pieces making up the scrap metal. If these pieces are mostly relativelylight weight turnings, drillings and borings, then a smaller total weight of sample can be taken from the car than if the scrap in the car is made up of larger, heavier scrap pieces, such asthose coming for instance from forging operations.

It is desirable to reduce the particle sizeof the samples taken from the aforementioned holes in the scrap car in order to enable it to pass through openings of one-half inch in a screen or strainer. Accordingly, a shredder .is preferably utilized, with a specific shredder used being one that has the capacity to handle from five to five hundred pounds of scrap sample in a matter of minutes, so that such scrap sample was reduced to one-half or one-quarter inch pieces in a matter of minutes. The reduced size samples are then mixed homogeneously together, and preferably exactly 724 grams of the shredded material of the original sample from the car is retained as a test sample for further processing.

The reason that it is preferred to use 724 grams for the test sample is merely to simplify the determination of the percent of metallics in the test sample when utilizing the formula A .7237+B=weight of metallics and times =percent of metallics where:

A =weight in grams of oxide formed by burning of test sample .7237=weight in grams of Fe in one gram of Fe O B=weight in grams of test sample taken (cg. 724).

It will be seen therefore that when E is the aforementioned 724 grams, it causes cancellation of the constant .7237, resulting in simplification of the calculation. It will be understood, however, that other weights of test sample could be used with the above 724 grams being taken only for convenience in calculation, since for all practical purposes, the oxide specimen obtained from the ferrous scrap sample is Fe Next this reduced weight test sample of 724 grams of the shredded sample may be enclosed in a combustible wrapper (such as a paper towel) and placed in a crucible of the type shown in FIGS. 2 and 3 of the drawings. Such crucible is preferably a graphite crucible having the tapered sides 11 and rounded bottom section 11a illustrated. The crucible is also preferably fitted with a removable lid 12 having a hole 14 disposed in the center thereof with such hole being of a relatively large diameter and with another smaller hole 16 on one side of the center hole. The small hole is adapted to receive a small diameter bare steel pipe oxygen lance for purging the air from the crucible during the original oxidizing period, as will be hereinafter described in greater detail.

After the 724 gram test sample that has been cut out of original sample has been placed in the crucible, oxygen (such as standard welding grade oxygen) may be inserted through the smaller hole 16 by means of an oxygen lance (not shown). Such lance preferably has an abutment thereon which is adapted for engagement with the exterior of the cover 12 around hole 16 and which prevents the lance from being inserted beyond or below the lid 12 and thus possibly being ignited during the initial oxidizing period. The oxygen may be turned on at a rate of about 2 liters per minute and is pumped into the crucible to purge all of the air from the crucible, with the air leaving by means of the larger center opening 14.

The sample in the crucible is then ignited such as for instance by dropping a lighted match through the large opening 14 in the crucible, which match ignites eitherthe wrapper, or oil if any, on the scrap, and which in turn starts oxidation or burning of the sample. Natural gas could also be used to initially support this burning. The

After the oxide button is weighed and based on the 724 gram initial test sample that was utilized for burning in the crucible, the weight of the oxide button formed divided by ten gives the percent of metallics in the sample, and as per the aforediscussed equation.

The oxide button is then taken and crushed into a maximum of one quarter inch particles for ease in handling of the sample. A suitable portion of such crushed button and which may be any desirable amount, is taken from such crushed material and further crushed into particles of about 100 mesh for analyzing. The oxide button processes very readily and crushes in an expeditious manner.

After reducing the desired amount of crushed oxide button sample to 100 mesh, the resultant powdered sample can be analyzed by conventional processes, such as for instance chemical, or optical emission spectrographic techniques, or X-ray spectrographic techniques. This analysis which is conventional and well known in the art, will depend upon the analytical equipment available to the analyzer. Analysis of such samples has shown that no significant loss of tramp elements is incurred in the scrap sample by this burning process, except for the elements carbon and sulphur which are lost during the burning process. Any of the above methods of analysis will give the weights of the specific tramp elements in the sample, and dividing by the convenient number 10 as aforediscussed, will give the percentages of such tramp elements in the representative sample of scrap.

The following identify National Bureau of Standards samples which were burned in the aforedescribed manner to obtain determinations of the phosphorous, chromium, arsenic, manganese copper, nickel molybdenum, silicon, vanadium, titanium, and tin found in such samples. Since the percentage of tramp elements were known in the National Bureau of Standards samples, the use of these standardized samples gave an excellent indication of the accuracy of the instant method. In the interests of convenience at the time of testing, a determination of all of the elements listed in the chart was not made for all samples tested.

RECOVERIES USING NATIONAL BUREAU OF STANDARDS STEEL AND CAST IRON SAMPLES Description of Sample Mn P Si Cu Ni Cr V Ti As Mo Al Sn National Bureau of Standards No 5-K- Present 536 26 2.08 1. 051 109 014 028 02 Found .55 .26 .122 0.15 .027 National Bureau of Standards No. 4-1:

Present 79 13 1. 45 253 062 1. 04 013 .026 .018

Found .135 1.47 .245 .060 .11 .017 National Bureau of Standards No. -1):

Present 73 015 .37 051 060 049 002 Found 015 052 .062 O51 National Bureau of Standards No.

Present 447 881 1. 89 021 011 O15 048 062 088 Found .45 .89 .017 .064 .090

oxygen blast intensifies the burning reaction, and which is exemplified by a slight glowing coming from the contrainer. The nearing of the completion of oxidation is indicated when the aforementioned glowing disappears and the pool of oxides begins to thicken and solidify. After the sample has been oxidized almost to completion which may vary from five minutes to twenty minutes depending upon the constituents or elements in the scrap sample utilized, the oxygen lance is removed from the small opening 16 and inserted through the large center hole 14 and held preferably about one inch above the molten pool of oxides in the crucible. The lance is then preferably rotated in a stirring-like action around the crucible by the operator to insure complete oxidation of any remaining metallics in the molten oxide. The lance may then be removed and the molten oxides are allowed to cool and solidify to form what is referred to as an oxide button.

In the present case taking a sample in accordance with the instant invention, the phosphorous was determined photometrically as molybdenum blue on the oxide sample. Arsenic was determiend by distillation as Arsenic Tribromide followed by molybdenum blue photometric finish. All of the other elements including chromium, manganese, vanadium, molybdenum, titanium, aluminum, copper, columbium, nickel, tin, lead and zinc were or may be determined spectrographically.

From the foregoing discussion and accompanying drawings it will be seen that the present invention comprises a novel method for obtaining a representative sample of scrap from a predetermined quantity of such scrap, and expeditiously determining the tramp elements in such sample, and a method that is not subject to the inherent errors present in prior art methods of sampling materials of this type. The method has been found to be reliable and the costly equipment and time consuming methods heretobefore utilized are eliminated.

The terms and expressions which have been used are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any of the equivalents of any of the features shown or described, or portions thereof, and it is recognized that various modifications are possible within the scope of the invention claimed.

I claim:

1. In a method providing a sample for metallurgical analysis the steps comprising, selecting an original sample from a quantity of ferrous material containing tramp elements, reducing the ferrous material into relatively small particle size, mixing the particles into a substantially homogeneous mixture, selecting a test sample of predetermined size from said mixture, introducing said test sample into a container, introducing a stream of oxygen into said container, igniting and burning the test sample in the presence of said oxygen for a time sufiicient to convert said test sample to a molten condition, said burning indicated by a glow emitted from said container, continuing to burn said material for a time sufiicent to convert the tramp elements of said test sample to molten oxides indicated by an initial disappearance of said glow, placing an oxygen introducing lance in close, spaced proximity to said molten oxides and moving said lance relative to said molten oxide with a stirring-like action to impart agitation to the molten oxides, allowing the molten oixdes to solidify into a solid mass, removing the solid mass from the container and reducing the solid mass into relatively fine particles size, and then analyzing the chemical composition of said particles.

2. In a method in accordance with claim 1, wherein the oxygen stream is introduced at the rate of about two liters per minute to purge all the air from said container prior to the ignition and burning of said test sample.

3. In a method in accordance with claim 1, wherein said ferrous material comprises iron scrap.

4. In a method in accordance with claim 1, wherein said test sample is deposited in a combustible wrapper for introduction into said container, and wherein said container comprises a graphite crucible.

5. In a method in accordance with claim 1, including the step of purging the air from said container by the introduction of said oxygen stream therein and by venting the air therefrom prior to the ignition of said test sample.

6. In a method in accordance with claim 1, wherein the particle size is about 100 mesh.

7. In a method in accordance with claim 1, including the step of reducing the ferrous material into about A-inch to /2-inch particle size, mixing the particles into a substantially homogeneous mixture, and then selecting a predetermined quantity from said mixture to give said test sample prior to the introduction thereof into said container.

8. In a method in accordance with claim 1, including the step of introducing an inflammable material into said container prior to ignition of the test sample to commence burning thereof.

9. A method in accordance with claim 1 wherein the analyzing is accomplished by means of chemical analysis.

10. A method in accordance with claim 1 wherein the analyzing is accomplished by means of optical emission spectrographic analysis.

11. A method in accordance with claim 1 wherein the analyzing is accomplished by X-ray spectrographic techniques.

12. A method of preparing a metallurgical test sample from iron scrap materials containing iron and tramp elements without any substantial loss of said tramp elements the steps comprising, selecting an original sample from said iron scrap material, reducing the original sample into relatively small particle size and mixing the particles into a substantially homogeneous mixture, selecting a predetermined quantity of material from the mixture to give a test sample, placing the test sample in a graphite crucible, introducing an oxidizing gas into the crucible in an amount suflicient to purge contained air from the crucible, igniting and burning the test sample in the presence of said oxidizing gas for a time sufficient to give a molten oxide pool, placing an oxygen lance in spaced, close proximity above said molten pool, introducing an oxygen stream through said lance and moving said lance with a stirring-like action for agitating the molten pool to convert the iron and tramp elements therein entirely into their oxides, allowing the molten oxides to cool and solidify to form an oxide button, reducing the oxide button into relatively fine particle size, and selecting a predetermined quantity of said particles for metallurgical analysis.

13. A method in accordance with claim 12, wherein burning of said test sample is indicated by a slight glow emitted from said chrucible, and wherein said burning continues for a time sulficient to provide a disappearance of said glow.

14. A method in accordance with claim 13, wherein said molten pool commences to thicken and solidify upon disappearance of said glow.

15. A method in accordance with claim 12, wherein the test sample has a weight of approximately 724 grams, the oxidizing gas is introduced into the crucible at a rate of approximately two liters per minute, and the burning continued for a period of between about 5 to 20 minutes.

16. A method in accordance with claim 12, wherein the original sample is reduced to between about A- inch to /2-inch particles, and the oxide button to minus 100 mesh size.

References Cited UNITED STATES PATENTS 2,809,100 10/1957 Krasl 23-253 2,836,482 5/1958 Dreher 23230 3,078,084 2/1963 Foresi et al. -43 X 3,138,452 6/1964 Aihara et al 7543 X 3,215,523 11/1965 Richardson 75-60 FOREIGN PATENTS 650,158 10/1962 Canada.

OTHER REFERENCES MORRIS O. WOLK, Primary Examiner. R. E. SERWIN, Assistant Examiner.

X-Ray Spectro- 

1. IN A METHOD PROVIDING A SAMPLE FOR METALLURGICAL ANALYSIS THE STEPS COMPRISING, SELECTING AN ORIGINAL SAMPLE FROM A QUANTITY OF FERROUS MATERIAL CONTAINING TRAMP ELEMENTS, REDUCING THE FERROUS MATERIAL INTO RELATIVELY SMALL PARTICLE SIZE, MIXING THE PARTICLES INTO A SUBSTANTIALLY HOMOGENEOUS MIXTURE, SELECTING A TEST SAMPLE OF PREDETERMINED SIZE FROM SAID MIXTURE, INTRODUCING SAID TEST SAMPLE INTO A CONTAINER, INTRODUCING A STREAM OF OXYGEN INTO SAID CONTAINER, IGNITING AND BURNING THE TEST SAMPLE IN THE PRESENCE OF SAID OXYGEN FOR A TIME SUFFICIENT TO CONVERT SAID TEST SAMPLE TO A MOLTEN CONDITION, SAID BURNING INDICATED BY A GLOW EMITTED FROM SAID CONTAINER, CONTINUING TO BURN SAID MATERIAL FOR A TIME SUFFICIENT TO CONVERT THE TRAMP ELEMENTS OF SAID TEST SAMPLE TO MOLTEN OXIDES INDICATED BY AN INITIAL DISAPPEARANCE OF SAID GLOW, PLACING AN OXYGEN INTRODUCING LANCE IN CLOSE, SPACED PROXIMITY TO SAID MOLTEN OXIDES AND MOVING SAID LANCE RELATIVE TO SAID MOLTEN OXIDE WITH A STIRRING-LIKE ACTION TO IMPART AGITATION TO THE MOLTEN OXIDES, ALLOWING THE MOLTEN OXIDES TO SOLIDIFY INTO A SOLID MASS, REMOVING THE SOLID MASS FROM THE CONTAINER AND REDUCING THE SOLID MASS INTO RELATIVELY FINE PARICLES SIZE, AND THEN ANALYZING THE CHEMICAL COMPOSITION OF SAID PARTICLES. 